The present invention relates to inflatable apparatus, and more specifically to such an inflatable apparatus, which provides high tensile strength, and the seams between the upper cover sheet and bottom cover sheet thereof are reinforced against leakage.
Regular inflatable apparatus, such as inflatable boats, beds and sofas, are commonly made by sealing PVC sheets into shape. FIG. 1A shows an inflatable boat of this design. The inflatable boat is comprised of an upper sheet 10 and a bottom sheet 10'. The inner peripheral edge and outer peripheral edge of the upper sheet 10 and the inner peripheral edge and outer peripheral edge of the bottom sheet 10' are respectively sealed together by, for example, a heat sealing apparatus, forming a respective seam R. As illustrated in FIG. 1B, when one peripheral edge of the upper sheet 10 and the corresponding peripheral edge of the bottom sheet 10' are attached together and pressed tight (see arrowheads A), and then welded together. When inflated, components of force are employed to each seam R in reversed directions F (see FIG. 1B). When a sudden compressive pressure is given to the inflatable boat, the seams R tend to be stretched open, causing an air leakage. In order to eliminate this problem, rubber material may be used for making an inflatable apparatus. However, the cost of rubber material is much higher than PVC sheet material. Further, a rubber inflatable apparatus is heavy, and low mobility. Therefore, except for professional use, most consumers do not accept rubber inflatable apparatus.